Methods and apparatus for voltage sensing and reporting

ABSTRACT

Semiconductor devices comprising at least one voltage sensor for sensing an operating voltage associated with an operational circuit of the semiconductor device. The at least one voltage sensor is configured to generate a signal indicative of a state of the operating voltage. Methods of monitoring a voltage in a semiconductor device include determining a magnitude of an operating voltage for an operational circuit in a semiconductor device. A signal may be generated indicating a state of the operating voltage.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/830,531, filed Jul. 30, 2007, now U.S. Pat. No. 7,692,996, issuedApr. 6, 2010, the disclosure of which is incorporated by referenceherein in its entirety.

FIELD OF THE INVENTION

Embodiments of the present invention relate to voltage sensors and,particularly, in one or more embodiments, to determining and reportingvarious voltages on a semiconductor device, sensing and reportingmethods, and systems including sensing and reporting capability.

BACKGROUND

Semiconductor devices, like most electronic products, are sensitive intheir operation to supplied voltage levels. If voltage levels at workingparts are lower than specified minimum requirements, the parts maymalfunction. If voltage levels are higher than specified maximumrequirements, the parts may malfunction and can also suffer catastrophicfailure. In semiconductor memory devices, for example, such as DynamicRandom Access Memories (DRAMs), inadequate voltage levels may causememory parts to malfunction by reading out or storing incorrectinformation. Such low voltage failures are often difficult to detect,and even when they are detected the resultant functional and data errorscan seldom be recovered.

Often, the semiconductor device is still operational when the voltagelevels become marginal causing the device to potentially fail in someaspect. For example, a memory device may not meet its full timingspecifications at low voltages, resulting in a failure to read correctdata. Even though the read data may be correct, the access time untilcorrect data is available may be longer than designated by the devicespecification. Similarly, a low voltage level may result in the memorydevice's bit-cell capacitors not having enough time to fully chargeduring a write cycle, even though they would work correctly if givenadditional time to complete the write cycle. In such a case, thebit-cells cannot be properly read and the data becomes corrupted.

There are many causes for unsuitable voltage levels to semiconductordevices, such as power supply errors and power distribution patheffects. Power supply errors may result when the power supply isinadequate, misadjusted, or fails altogether. Power distribution patheffects influence voltage levels, for example, through transient noisesignals, inductance, and/or resistance in power distribution paths. Assemiconductor device activity increases, these power distribution patheffects often add together and further increase the chances of data andfunctional errors.

Historically, voltage sensors have been used to detect the voltagelevels coming directly from the power supplies. However, these devicesare limited to sensing voltage errors in the supply voltage. Thesesystems are not capable of detecting whether voltage levels areunsuitable at specific locations (e.g., circuits) within thesemiconductor device itself. Thus, these devices do not detectunsuitable voltage levels not caused by the voltage source itself, suchas the distribution path effects described above.

In view of the shortcomings in the prior art, it would be advantageousto provide a semiconductor device capable of sensing and/or reportingvoltage levels at operational circuits within the semiconductor device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a semiconductor memory deviceincluding a voltage sensing and reporting device according to oneembodiment of the invention.

FIG. 2 illustrates a voltage sensing and reporting device includingnumeric result reporting according to one embodiment of the invention.

FIG. 3 is a memory card containing a plurality of semiconductor memorydevices containing a voltage sensing and reporting device according toone embodiment of the invention.

FIG. 4 is a computing system diagram showing a plurality ofsemiconductor memories containing a voltage sensing and reporting deviceaccording to one embodiment of the invention.

FIG. 5 is a flow diagram illustrating a method for sensing and reportingvoltage in a semiconductor memory device according to one embodiment ofthe invention.

DETAILED DESCRIPTION

In the following detailed description, circuits and functions may beshown in block diagram form in order not to obscure the presentinvention in unnecessary detail. Additionally, block definitions andpartitioning of logic between various blocks as depicted isnon-limiting, and comprise examples of only specific implementations. Itwill be readily apparent to one of ordinary skill in the art that thepresent invention may be practiced in a variety of embodimentsimplementing numerous other partitioning solutions.

Also, it is noted that the embodiments may be described in terms of aprocess that is depicted as a flowchart, a flow diagram, a structurediagram, or a block diagram. Although a flowchart may describeoperational acts as a sequential process, many of these acts can beperformed in another sequence, in parallel, or substantiallyconcurrently. In addition, the order of the acts may be re-arranged. Aprocess is terminated when its acts are completed. A process maycorrespond to a method, a function, a procedure, a subroutine, asubprogram, etc. When a process corresponds to a function, itstermination corresponds to a return of the function to the callingfunction or the main function.

FIG. 1 is a block diagram illustrating a semiconductor memory device 100including a voltage sensing and reporting device according to oneembodiment. The semiconductor memory device 100 may be a DRAM withconventional memory banks and operational circuits 140 and be controlledby conventional address, command, and data buses 142. Semiconductormemory device 100 includes at least one voltage sensor 110 for sensingvoltages. The at least one voltage sensor 110 may include a voltagecomparator configured according to any of the known configurations inthe art. The voltage comparator may be configured to compare anoperating voltage (108A, 108B), such as V_(dd) or V_(ddq), to areference voltage (102A, 102B), such as V_(ref) or V_(ref2), fordetermining a voltage difference. The term “voltage difference,” as usedherein, refers to a quantifiable difference between the operatingvoltage level and the reference voltage level, which difference may beexpressed as a numerical value.

The operating voltage (108A, 108B) may be a supply voltage 108A from aninput pin or may be an operating voltage 108B generated internally onthe semiconductor memory device 100. The operating voltage (108A, 108B)may be configured to supply a voltage to one or more operationalcircuits 140 of the semiconductor memory device 100. By way of exampleand not limitation, operational circuits 140 may include column decodercircuits, write driver circuits, data read and write multiplexers, DCsense amplifiers, etc. Although FIGS. 1 and 2 illustrate the operatingvoltage (108A, 108B) coupled to operational circuits 140, one ofordinary skill in the art will recognize that the operating voltage(108A, 108B) may be further coupled to other elements in FIGS. 1 and 2although it may not be specifically illustrated.

Similar to the operating voltage (108A, 108B), the reference voltage(102A, 102B) may be a supply voltage 102A from an input pin to thesemiconductor device, or the reference voltage may be a referencevoltage 102B generated internally on the semiconductor memory device 100in any manner known in the art. By way of example and not limitation,the internally generated reference voltage 102B may be generated from asimple resistor voltage divider, a voltage drop generated by aforward-biased diode, a reverse-biased Zener diode, or a bandgapreference circuit. Since different circuits of the semiconductor devicemay require different voltage levels, there may be more than onereference voltage in semiconductor memory device 100. The referencevoltage, as known in the art, may be characterized as a substantiallyconstant voltage within conventional tolerances. In some embodiments,the reference voltage may comprise a ground as opposed to an actualvoltage level.

The at least one voltage sensor 110 may be configured to compare thedifferent reference voltages with different operating voltages. As anon-limiting example, voltage sensor 110 may be set to compare a firstreference voltage V_(ref) with a first operating voltage V_(dd). Voltagesensor 110 may further be set to compare a second voltage referenceV_(ref2) with a second operating voltage V_(ddq). It will be apparent toone of ordinary skill in the art that it is possible to compare aplurality of reference voltages with a plurality of operating voltagesaccording to numerous combinations, including the disposition of morethan one voltage sensor 110 on the semiconductor memory device 100. Insome embodiments, a single voltage sensor 110 may be operably connectedto compare a plurality of operating voltages to one or more referencevoltages as described below.

Further, a voltage sensor 110 may be configured to signal an alarm inthe case where the operating voltage is outside of a range. As usedherein, “range” signifies the magnitude of the voltage is beyond apredetermined threshold level, which may be an upper or lower levelrelative to an expected, or normal operating voltage, and is not to beread as requiring the device to necessarily have an operating rangesensed between an upper and a lower threshold. In some embodiments, thevoltage sensor 110 may be configured to signal an alarm when theoperating voltage is above an upper threshold or below a lowerthreshold, as determined from comparison with the reference voltage. Inother embodiments, the voltage sensor 110 may be configured to signal analarm only when the voltage level is below a lower threshold, whilehaving no upper limit. In still other embodiments the voltage sensor 110may be configured to signal an alarm only when the voltage level isabove an upper threshold. Thus, use of the term “range” herein is notlimited to embodiments requiring upper and lower thresholds.

If the operating voltage is above or below the relevant threshold,voltage sensor 110 may indicate the voltage failure by sending a flagsuch as alarm signal 112 to a pin on semiconductor memory device 100 forsignaling the alarm externally. It is contemplated that voltage sensor110 may be coupled to, and share a previously existing pin onsemiconductor memory device 100, such as, for example, a boundary scanpin. One of ordinary skill in the art will recognize that any existingpin suitable for sharing may be used to communicate the voltage sensoroutput. Alternatively, a new pin may be provided on semiconductor memorydevice 100 with which voltage sensor 110 may be associated. As describedabove, there may be more than one voltage supplied within thesemiconductor memory device 100. In this case a voltage sensor 110 maybe provided for each supplied voltage, or, as described above, voltagesensor 110 may be configured to compare multiple reference voltages tomultiple operating voltages. In the case where a voltage sensor 110 isprovided for each voltage, the outputs for each of the voltage sensorsmay be connected to the same output pin through an optional outputcontroller 114. By way of non-limiting example, output controller 114may be configured as one or more logic “OR” gates, or as a multiplexer.

As stated, the pin on semiconductor memory device 100 for carrying thealarm signal 112 externally may be configured as a boundary scan outputpin or other internal scan output pin. When not configured forperforming a scan function, the scan output pin may be configured tocarry the output from the output controller 114 (if present) or directlycarry the alarm signal 112. For example, the pin can serve to carry thealarm signal 112 externally during normal operation, when scan functionsor other similar functions are not being carried out. When placed into amaintenance or scan mode, the pin may be configured to carry out suchother function or functions instead of carrying the alarm signal 112.

The output pin may be operably coupled to any suitable externalcomponent, which may also be characterized as an external module. By wayof example and not limitation, the output pin may be operably coupled toa memory controller, to receive the alarm signal 112 from the at leastone voltage sensor 110. Upon receiving the alarm signal 112, the memorycontroller may be configured to adjust an operating parameter for thesemiconductor memory device 100. As a non-limiting example, the memorycontroller may adjust the timing, and/or the power voltage levels forthe semiconductor memory device 100. Adjusting the timing may allow moretime to complete operations of the semiconductor memory device 100. Forexample, the adjustment may provide semiconductor memory device 100 withmore time to complete reading and writing operations.

In another embodiment, and as a non-limiting example, the output pin ofthe semiconductor memory device 100 may be operably coupled to amaintenance system. The maintenance system may be configured to adjustan operating parameter for the semiconductor memory device 100 uponreceiving the alarm signal 112. In still another embodiment, the outputpin may be operably coupled to both a maintenance system and a memorycontroller.

With further reference to FIG. 1, a mode register 120 may be operablycoupled to voltage sensor 110 and configured to control the operation ofvoltage sensor 110. By way of example and not limitation, mode register120 may be an existing mode register within semiconductor memory device100. For example, mode register 120 may be a mode register used foranother function in semiconductor memory device 100. Alternatively, moderegister 120 may be added as a unique register to the circuitarchitecture of semiconductor memory device 100. For example, moderegister 120 may be added in an unused extended mode register positionconventionally found in current DRAMs. The mode register 120 may becontrolled and written to using conventional memory device commands.Mode register 120 may be configured to control voltage sensor 110 withone or more bits. At least one bit may be provided and used to enableand disable voltage sensor 110. One or more additional bits may beprovided and used to select which voltage reference is to be used whenthere are more than one voltage references available. Additionally, moderegister 120 may be configured to provide one or more bits for selectingwhich operating voltage to compare in the case that there are more thanone operating voltages. In the case where there may be more than onevoltage sensor 110, one or more bits may be provided from mode register120 to control additional voltage sensors. Mode register 120 may also beused to define and enable the adjustment of the upper and lowerthreshold value for each of the operating voltages (108A and 108B). Moderegister 120 may additionally be used to select which voltage sensor 110may communicate through the output pin on the semiconductor memorydevice 100. In some embodiments, mode register 120 may be coupled tooutput controller 114 to control the operations of output controller114.

One of ordinary skill in the art will recognize that multiple moderegisters may be used instead of just one, as described above, inappropriate situations. As a non-limiting example, a different moderegister may be used to control each of a plurality of voltage sensors110 on the semiconductor memory device 100. In addition, another moderegister may be used to select which voltage sensor 110 is communicatingthrough the alarm signal 112. The additional mode register may select avoltage sensor directly to communicate through the alarm signal 112, orthe mode register may select which voltage sensor may communicate bycontrolling output controller 114. In addition, if the alarm signal 112is configured on a scan output pin, the mode register 120 may controlwhether the scan output pin is configured to carry the alarm signal 112,or conventional scan output signals.

As described above, in some embodiments a single voltage sensor 110 maybe operably connected to compare a plurality of operating voltages toone or more reference voltages. In these embodiments, a multiplexer 150(shown in broken lines in FIG. 1) may be employed to control whichoperating voltage is being compared with a reference voltage. Themultiplexer 150 may further control the duration of time each operatingvoltage is compared with the reference voltage. A suitable multiplexer150 may comprise transmission gates so that the operating voltages aresent through the multiplexer 150 to the voltage sensor 110.Additionally, a suitable multiplexer 150 may exhibit an impedance thatis relatively low compared to the other transmission line impedances. Insuch embodiments, a mode register as described above may be employed tocontrol the multiplexer 150 and the rate at which the differentoperating voltages are compared.

Additionally, one of ordinary skill in the art will recognize thatembodiments of the present invention may be configured without a moderegister. As a non-limiting example, a voltage sensor 110 may beconfigured to compare a single operating voltage (108A or 108B) with asingle reference voltage (102A or 102B) and to generate alarm signal 112in the case the voltage difference is greater than a preset level.

FIG. 2 illustrates a voltage sensing and reporting device includingnumeric result reporting according to one embodiment. At least onevoltage sensor 110 may include an analog-to-digital (A/D) converter 111.A/D converters are well known in the art and any suitable AID convertermay be employed. The A/D converter 111 may be used to convert thevoltage difference between the reference voltage (102A, 102B) and theoperating voltage (108A, 108B) to a numeric value specified by one ormore bits. In embodiments in which the reference voltage is a ground, asdescribed above, the A/D converter 111 may be used to convert theoperating voltage to a numeric value relative to the ground. An outputregister 130 may be operably coupled to an output of the A/D converter111 and configured to receive and store the numeric value of the voltagedifference from the at least one voltage sensor 110. As a non-limitingexample, an operating voltage that is too low may be sensed in a voltagesensor 110 and compared to the reference voltage. The value of thevoltage difference may be indicated by a numeric value converted by theA/D converter 111. The numeric value may be in the form of a pluralityof bits such as, for example, a byte. The numeric value may be sent fromthe A/D converter 111 to the output register 130 either serially, ifthere is only a single communication line, or through a bus (not shown).The numeric value may be stored in output register 130. Output register130 may be further operably coupled to the same output pin configured tocarry alarm signal 112 and may be configured to send the numeric valueserially to the output pin as either part of or separate from a scanpath.

As described above, the output pin may be operably coupled to anysuitable external component, which may also be described as an externalmodule, such as a memory controller, a maintenance system, etc. Inembodiments similar to that illustrated in FIG. 2, the suitable externalcomponent may receive the alarm signal 112 generated by the voltagesensor 110. By way of example and not limitation, the suitable externalcomponent may comprise a memory controller. Upon receipt of the alarmsignal 112, the memory controller may send control bits to the moderegister(s) 120 indicating that output register 130 should send itscontents out on the alarm signal 112 in a serial fashion. The moderegister 120 may control the output register 130 and output controller114 to cause the serial output to occur. As with the alarm signals, theoutput register content may be serially scanned out on a dedicatedsignal pin, another multiple function pin, an internal scan pin, aboundary scan pin, etc.

In some embodiments, as described above, mode register 120 may beoperably coupled and configured to control output register 130. Similarto FIG. 1, above, mode register 120 may be the same mode register usedto control voltage sensor 110 and/or output controller 114. In otherembodiments, mode register 120 may be a separate mode register from themode register configured to control voltage sensor 110 and outputcontroller 114. Mode register 120 may provide one or more bits forcontrolling the operation of output register 130.

Similar to FIG. 1, above, the embodiment illustrated in FIG. 2 mayinclude a single voltage sensor 110 operably connected to compare aplurality of operating voltages to one or more reference voltages. Theseembodiments may include the multiplexer 150 as described above withrelation to FIG. 1.

As shown in FIG. 3, a substrate 200, such as a printed circuit board(PCB), in accordance with an embodiment of the present invention,includes a plurality of semiconductor memory devices 100′, at least oneof which incorporates at least one embodiment of a voltage sensing andreporting device as described herein. It should be understood that eachsemiconductor memory device 100′ might comprise one of a wide variety ofdevices, including, for example, Dynamic RAM (DRAM) devices, Static RAM(SRAM) devices, and Flash memory devices. The output pin configured tocarry the alarm signal of each of the semiconductor memory devices 100′that support the voltage sensing function may be operably coupled to asuitable external component, which may also be characterized as setforth above as an external module that is configured to receive thealarm signal 112. For example, the output pins may be operably coupledto a memory controller 220 through a memory controller interface 210.Upon receiving the alarm signal 112, the memory controller 220 mayadjust an operating parameter as described above. As shown in FIG. 4, anelectronic system 300, such as a computer system, in accordance with anembodiment of the present invention, comprises at least one input device310, at least one output device 320, at least one processor 330, and atleast one memory device 340. As used herein, the term “computer system”includes not only computers, such as personal computers and servers, butalso wireless communications devices (e.g., cell phones, personaldigital assistants configured for text messaging and email), cameras,chip sets, set top boxes, controllers, vehicle and engine control andsensor systems, and other combinations of the above-referenced input,output, processor and memory devices. The at least one memory device 340comprises at least one semiconductor memory device 100 incorporating atleast one of the voltage sensing and reporting devices described hereinaccording to an embodiment of the invention. As a non-limiting example,each memory device 340 may comprise a module configured as a substrate200 bearing multiple semiconductor memory devices 100′ as is illustratedin FIG. 3. It should be understood that the semiconductor memory devices100′, may be selected from a wide variety of devices, including, forexample, Dynamic RAM (DRAM) devices, Static RAM (SRAM) devices, Flashmemory devices, and combinations thereof.

Furthermore, embodiments of the present invention can be implemented intypes of semiconductor devices other than memories. By way ofnon-limiting example, embodiments of the present invention may beimplemented in microprocessors, microcontrollers, system-on-a-chip, andimage sensors. As a non-limiting example, in a microprocessor ormicrocontroller, clock speed, execution unit operation, and memoryaccess times may be adjusted responsive to results from the voltagesensor 110 (FIGS. 1 and 2). As another non-limiting example, in an imageprocessor, operational parameters, such as integration time, pixel resettimes, pixel reset voltages, analog-to-digital conversion operations,and signal processing operations, such as bit repairs and imagecompression, may be adjusted responsive to results from the voltagesensor 110.

One of ordinary skill in the art will recognize that when implemented insemiconductor devices other than memories, the mode register(s) used tocontrol the voltage sensor 110, output controller 114, and outputregister(s) 130 would be written to using command appropriate for thesemiconductor device rather than conventional memory commands that maybe used in a DRAM or Flash memory device.

FIG. 5 illustrates one embodiment of a method of sensing and reportingvoltage levels in a semiconductor memory device. A reference voltage maybe generated at 510. The reference voltage may be generated, forexample, from a power supply, a simple resistor voltage divider, avoltage drop generated by a forward-biased diode, a reverse-biased Zenerdiode, a bandgap reference circuit, an external voltage source, or anyother method known to those of ordinary skill in the art. The referencevoltage may be compared to an operating voltage in a voltage sensor at520. The reference voltage and operating voltage may be compared in avoltage comparator. The voltage sensor may determine whether theoperating voltage is within an acceptable range above an upper thresholdor below a lower threshold at 530. If the operating voltage is withinnormal operating conditions, e.g., below the upper threshold and abovethe lower threshold, the process returns to comparing the operatingvoltage with the reference voltage. If, however, the operating voltageis outside of the normal operating range, e.g., below a lower thresholdor above an upper threshold, an alarm signal may be generated at 540.The upper and lower thresholds selected may vary according to thespecific application. In some embodiments, the sequence illustrated inFIG. 5 may end at this point and may use an external device (e.g., amaintenance system) for providing outside support, such as adjustmentsto one or more operational parameters.

In other embodiments, a numeric value indicative of the operatingvoltage may be generated at 550. The numeric value may then be storedfor later retrieval at 560, and the stored numeric value may beretrieved and read by another device at 570. By way of example, and notlimitation, the numeric value may be stored in an output register, andretrieved by a control module. Those of ordinary skill in the art willrecognize that the numeric value may be stored in any suitable registeror memory location. Additionally, the alarm, the numeric value, or both,may be made available to any external module determined by the designerto be suitable. By way of example and not limitation, the alarm, thenumeric value, or both, may be made available to at least one of amemory controller and a maintenance system. Adjustments may be made toone or more operational parameters on the semiconductor memory device tocompensate for the power issues based on at least one of the alarmsignal and the numeric value at 580.

CONCLUSION

In one embodiment of the present invention a semiconductor device mayemploy at least one reference voltage. At least one operating voltagemay be employed, associated with at least one circuit of thesemiconductor device. At least one voltage sensor is configured tocompare the at least one reference voltage and the at least oneoperating voltage. The voltage sensor may, optionally, be configured togenerate an alarm signal if a difference between the operating voltageand the reference voltage is greater than a predetermined amount.

In another embodiment of the invention, a memory card comprising aplurality of memory devices is provided. At least one of the memorydevices is configured with at least one voltage sensor as describedabove.

Another embodiment of the invention comprises an electronic system. Theelectronic system may include at least one input device, at least oneoutput device, a processor, and at least one memory device configuredwith at least one voltage sensor as described above.

An embodiment of a method for sensing and reporting a voltage in asemiconductor device is also provided, the method including comparing anoperating voltage to a reference voltage and determining whether theoperating voltage is outside a predetermined voltage range. The methodmay further include generating an alarm signal when the operatingvoltage is outside the predetermined voltage range.

While certain embodiments have been described and shown in theaccompanying drawings, such embodiments are merely illustrative and notrestrictive of the scope of the invention, and this invention is notlimited to the specific constructions and arrangements shown anddescribed, since various other additions and modifications to, anddeletions from, the described embodiments will be apparent to one ofordinary skill in the art. Thus, the scope of the invention is onlylimited by the literal language, and equivalents, of the claims whichfollow.

What is claimed is:
 1. A semiconductor device, comprising: at least onevoltage sensor for sensing an operating voltage associated with anoperational circuit of the semiconductor device, the at least onevoltage sensor for generating a signal indicative of a state of thesensed operating voltage; and at least one output pin coupled to the atleast one voltage sensor, the at least one output pin for carrying thesignal generated by the at least one voltage sensor to an externalcomponent for modifying at least one operating parameter of theoperational circuit.
 2. The semiconductor device of claim 1, wherein thestate of the operating voltage comprises at least one of the sensedoperating voltage being beyond a predetermined threshold and a numericvalue related to the sensed operating voltage.
 3. The semiconductordevice of claim 1, wherein the at least one voltage sensor comprises avoltage comparator for comparing the sensed operating voltage to atleast one reference voltage.
 4. The semiconductor device of claim 1,wherein the at least one output pin is a boundary scan output pin. 5.The semiconductor device of claim 1, wherein the at least one operatingparameter of the operational circuit comprises at least one of timingand power voltage levels.
 6. The semiconductor device of claim 4,further comprising at least one mode register configured to control theat least one output pin to selectively change between carrying at leastone of the signal generated by the at least one voltage sensor and atleast one other scan output signal.
 7. The semiconductor device of claim1, further comprising at least one mode register operably coupled to theat least one voltage sensor and configured to control operation of theat least one voltage sensor.
 8. The semiconductor device of claim 7,wherein the at least one mode register is configured to perform at leastone of the following functions: enable/disable the at least one voltagesensor; define an upper and a lower threshold value for the at least onevoltage sensor; and if the at least one voltage sensor comprises aplurality of voltage sensors, select a voltage sensor of the pluralityof voltage sensors to generate a signal.
 9. A semiconductor device,comprising: at least one voltage sensor for sensing an operating voltageassociated with an operational circuit of the semiconductor device andto generate a signal comprising a numeric value indicative of amagnitude of the sensed operating voltage; and at least one output pincoupled to the at least one voltage sensor, the at least one output pinfor delivering the signal to an external component to modify at leastone operating parameter of the operational circuit.
 10. Thesemiconductor device of claim 9, wherein the at least one voltage sensoris configured to compare the sensed operating voltage to at least onereference voltage to determine the magnitude of the sensed operatingvoltage.
 11. The semiconductor device of claim 9, wherein the at leastone voltage sensor comprises an analog-to-digital converter configuredto convert the magnitude of the sensed operating voltage to the numericvalue.
 12. The semiconductor device of claim 9, further comprising anoutput register coupled to the at least one voltage sensor to receiveand store the numeric value.
 13. The semiconductor device of claim 12,wherein the output register is to receive the numeric value serially ona single communication line between the output register and the at leastone voltage sensor.
 14. The semiconductor device of claim 12, whereinthe output register is coupled to the output pin to selectively carrythe numeric value external to the semiconductor device.
 15. Thesemiconductor device of claim 9, wherein the signal comprising thenumeric value comprises a plurality of bits.
 16. A method of monitoringa voltage in a semiconductor device, comprising: determining a magnitudeof an operating voltage for an operational circuit in a semiconductordevice; generating a signal indicative of a state of the operatingvoltage; and communicating the signal externally through at least oneoutput pin to an external component to modify at least one operatingparameter of the operational circuit.
 17. The method of claim 16,wherein determining the magnitude of the operating voltage comprisescomparing the operating voltage to a reference voltage.
 18. The methodof claim 16, wherein generating the signal indicative of the state ofthe operating voltage comprises generating the signal indicative of atleast one of the magnitude of the operating voltage being beyond athreshold level and a numeric value relating to a voltage level of theoperating voltage.
 19. The method of claim 16, wherein communicating thesignal externally through at least one output pin comprisescommunicating the signal externally through at least one internal scanoutput pin.
 20. The method of claim 19, wherein communicating the signalexternally comprises communicating the signal to at least one of amemory controller and a maintenance system.